<div dir="ltr"><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">I'm trying to build <code style="margin:0px;padding:1px 5px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;background-color:rgb(239,240,241);white-space:pre-wrap">coro.c</code> using Clang+LTO.</p><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">When I link together the final binary, I get the following error:</p><pre style="margin-top:0px;margin-bottom:1em;padding:5px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;width:auto;max-height:600px;overflow:auto;background-color:rgb(239,240,241);word-wrap:normal;color:rgb(36,39,41)"><code style="margin:0px;padding:0px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;white-space:inherit">Global is external, but doesn't have external or weak linkage!
void ()* @coro_transfer
</code></pre><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">The symbol is defined in <code style="margin:0px;padding:1px 5px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;background-color:rgb(239,240,241);white-space:pre-wrap">coro.h</code> as:</p><pre style="margin-top:0px;margin-bottom:1em;padding:5px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;width:auto;max-height:600px;overflow:auto;background-color:rgb(239,240,241);word-wrap:normal;color:rgb(36,39,41)"><code style="margin:0px;padding:0px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;white-space:inherit">#if __i386__ || __x86_64__
extern void __attribute__ ((__noinline__, __regparm__(2)))
#else
extern void __attribute__ ((__noinline__))
#endif
coro_transfer (coro_context *prev, coro_context *next);
</code></pre><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">and in <code style="margin:0px;padding:1px 5px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;background-color:rgb(239,240,241);white-space:pre-wrap">coro.c</code> as:</p><pre style="margin-top:0px;margin-bottom:1em;padding:5px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:13px;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;width:auto;max-height:600px;overflow:auto;background-color:rgb(239,240,241);word-wrap:normal;color:rgb(36,39,41)"><code style="margin:0px;padding:0px;border:0px;font-style:inherit;font-variant:inherit;font-weight:inherit;font-stretch:inherit;line-height:inherit;font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;vertical-align:baseline;white-space:inherit">  asm (
       "\t.text\n"
       #if _WIN32 || __CYGWIN__ || __MACH__
       "\t.globl _coro_transfer\n"
       "_coro_transfer:\n"
       #else
       "\t.globl coro_transfer\n"
       "coro_transfer:\n"
       #endif
</code></pre><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">It seems to me that it does have (or should) have global linkage. Is this a bug with LTO, or is there something wrong with the assembly definition?</p><p style="margin:0px 0px 1em;padding:0px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;font-size:15px;line-height:inherit;font-family:Arial,"Helvetica Neue",Helvetica,sans-serif;vertical-align:baseline;clear:both;color:rgb(36,39,41)">I checked with nm and noticed the symbol was first undefined and then defined. I guess that's because of the declaration in the header but it's not technically a C function in the implementation.</p><pre style="margin-top:0px;margin-bottom:1em;padding:5px;border:0px;font-variant-numeric:inherit;font-stretch:inherit;line-height:inherit;vertical-align:baseline;width:auto;max-height:600px;overflow:auto;background-color:rgb(239,240,241);word-wrap:normal"><font color="#242729" face="Consolas, Menlo, Monaco, Lucida Console, Liberation Mono, DejaVu Sans Mono, Bitstream Vera Sans Mono, Courier New, monospace, sans-serif"><span style="font-size:13px">coro.c.o:
         U abort
00000000 T coro_create
00000000 T coro_stack_alloc
00000000 T coro_stack_free
         U coro_transfer
00000000 T coro_transfer
         U mmap
         U mprotect
         U munmap
         U sysconf</span></font><span style="color:rgb(36,39,41);font-family:Consolas,Menlo,Monaco,"Lucida Console","Liberation Mono","DejaVu Sans Mono","Bitstream Vera Sans Mono","Courier New",monospace,sans-serif;font-size:13px">
</span></pre><div>Could this be causing the problem?</div><div><br></div><div>Thanks for any ideas or suggestions.</div><div><br></div><div>Kind regards,</div><div>Samuel</div></div>